Fisher Stove Grandma Bear Smoking Too Much? (Pro Woodburner Fixes)

Upgrading Your Grandma Bear: Taming the Smoke Monster

Let’s talk about a classic: the Fisher Stove Grandma Bear. These stoves are legendary for their heating power, their robust construction, and… well, sometimes, their tendency to smoke a bit more than we’d like. I’ve spent years working with wood stoves, old and new, and I’ve learned a thing or two about keeping them burning clean and efficiently. I can still remember the first time I encountered a smoking Grandma Bear. It was at a friend’s cabin, and the entire place smelled like a campfire gone wrong. We spent hours troubleshooting, and that experience sparked my fascination with wood stove optimization.

Understanding Why Your Grandma Bear is Smoking

Before we dive into the fixes, let’s understand why your stove might be producing excessive smoke. Smoke is a sign of incomplete combustion – meaning the wood isn’t burning as efficiently as it should. Several factors can contribute to this:

• Insufficient Air Supply: Wood needs oxygen to burn properly. If your stove isn’t getting enough air, the wood will smolder and produce smoke.
• Wet or Unseasoned Wood: This is the most common culprit. Wet wood requires a lot of energy to evaporate the moisture, leaving less energy for combustion.
• Poor Chimney Draft: A strong chimney draft is essential for pulling smoke out of the stove and creating a proper airflow.
• Creosote Buildup: Creosote is a flammable byproduct of incomplete combustion that accumulates in the chimney. Excessive buildup can restrict airflow and increase the risk of chimney fires.
• Improper Loading Techniques: How you load the wood into the stove can significantly impact its performance.
• Stove Design Limitations: Older stoves like the Grandma Bear, while robust, lack some of the advanced combustion technology found in modern stoves.

Diagnosing the Problem: A Step-by-Step Approach

Okay, let’s get down to business. Here’s how I approach diagnosing a smoky Grandma Bear.

Step 1: Check Your Wood

• Moisture Content is Key: I cannot stress this enough. The ideal moisture content for firewood is below 20%. Use a moisture meter to test your wood. I recommend the General Tools MMD4E Digital Moisture Meter; it’s affordable and reliable. If your wood reads above 20%, it needs more seasoning time. Wood that hisses and steams when burned is too wet.
• Seasoning Time: Hardwoods like oak and maple typically need at least 12-18 months of seasoning. Softwoods like pine can season in as little as 6 months, but they also burn faster.
• Wood Storage: Stack your wood off the ground, in a sunny and windy location, to promote air circulation. A good woodshed or covered stack is ideal.

Step 2: Inspect Your Chimney

• Visual Inspection: Check for any visible obstructions, such as bird nests or debris. Look for excessive creosote buildup.
• Chimney Sweep: If you haven’t had your chimney professionally cleaned recently, schedule an appointment. A clean chimney is a safe chimney. I typically recommend cleaning every year or two, depending on how frequently you use the stove.
• Draft Test: Light a small piece of newspaper and hold it near the stove’s flue opening. If the smoke is drawn quickly up the chimney, your draft is good. If the smoke lingers or wafts back into the room, you have a draft problem.

Step 3: Assess Airflow

• Air Intake: Ensure the air intake on your stove is clear of obstructions. Some older stoves have a manual damper that needs to be adjusted.
• Door Seal: Check the door gasket for damage or wear. A leaky door can disrupt the airflow and cause smoke to escape into the room. You can test the seal by closing the door on a dollar bill. If you can easily pull the bill out, the seal is compromised. Replace worn gaskets with a high-temperature stove gasket. I prefer graphite-impregnated gaskets for their longevity and sealing properties.
• Ash Buildup: Excessive ash buildup in the firebox can restrict airflow. Clean out the ash regularly. I typically remove ash every 2-3 days when burning frequently.

Step 4: Evaluate Loading Techniques

• Top-Down Burning: I’ve found this technique to be particularly effective in reducing smoke. Start by placing larger pieces of wood at the bottom of the firebox, followed by smaller kindling and a fire starter on top. This allows the fire to burn down slowly and efficiently, reducing smoke production.
• Avoid Overloading: Don’t cram too much wood into the stove. This can restrict airflow and lead to incomplete combustion. Leave some space around the wood for air to circulate.
• Orientation: Position the wood so that air can circulate freely around each piece. I prefer to stack wood in a crisscross pattern to maximize airflow.

Pro Woodburner Fixes: Taking it to the Next Level

Now that we’ve covered the basics, let’s get into some more advanced techniques for optimizing your Grandma Bear’s performance.

1. The Chimney Extension:

• The Problem: If your chimney is too short, it may not generate enough draft. This is especially common in homes with complicated rooflines or nearby trees that can disrupt airflow.
• The Fix: Adding a chimney extension can significantly improve draft. Consult with a qualified chimney professional to determine the appropriate height for your chimney. Building codes often dictate minimum chimney heights based on roof pitch and proximity to other structures. A chimney that extends at least 2-3 feet above the highest point of the roof within a 10-foot radius is generally recommended.
• Materials: Use the same type of chimney pipe as your existing chimney. Stainless steel is a durable and long-lasting option.
• Installation: This is best left to a professional. Improper installation can create a fire hazard.

2. The Barometric Damper:

• The Problem: Overly strong draft can also cause problems. It can pull heat out of the stove too quickly and lead to inefficient burning.
• The Fix: A barometric damper regulates the draft by allowing outside air to enter the chimney when the draft is too strong. This stabilizes the draft and improves combustion efficiency.
• Installation: Install the barometric damper in the stovepipe, as close to the stove as possible. Adjust the damper to maintain a consistent draft. Consult the manufacturer’s instructions for proper adjustment.

3. The Catalytic Combustor (Retrofit):

• The Problem: Grandma Bear stoves are pre-EPA regulations, meaning they lack the advanced combustion technology found in modern stoves.
• The Fix: While not a direct retrofit from the manufacturer (because there isn’t one), adding a catalytic combustor can dramatically reduce smoke emissions and improve efficiency. This involves modifying the stove to accommodate a catalytic combustor, which burns off the smoke and gases produced during combustion.
• Considerations: This is an advanced modification that requires welding and fabrication skills. It’s not for the faint of heart. You’ll need to research aftermarket catalytic combustor kits and adapt them to fit your Grandma Bear. This involves cutting an opening in the stove’s baffle and installing a bypass damper to protect the combustor during startup and refueling.
• Benefits: Reduced smoke, increased heat output, and improved fuel efficiency.
• My Experience: I retrofitted a catalytic combustor into an old Jotul stove a few years back. The results were remarkable. The stove burned cleaner, produced more heat, and used significantly less wood. However, it was a time-consuming project that required careful planning and execution.

4. The Baffle Upgrade:

• The Problem: The original baffle in your Grandma Bear may be worn or inefficient.
• The Fix: Replacing or upgrading the baffle can improve combustion efficiency. The baffle is a metal plate that sits inside the firebox, above the fire. It forces the hot gases to travel further before exiting the stove, allowing more time for combustion.
• Options: You can fabricate a new baffle from thicker steel or modify the existing baffle to improve its performance. Adding a secondary air supply to the baffle can also enhance combustion.
• Materials: Use high-temperature steel that is at least 1/4 inch thick.
• Design: The baffle should cover at least two-thirds of the firebox’s width.
• My Insight: I once experimented with different baffle designs in an old Vermont Castings stove. I found that a baffle with a series of small holes drilled into it created a more turbulent airflow, which improved combustion efficiency.

5. The Firebox Insulation:

• The Problem: Heat loss through the firebox walls can reduce the stove’s efficiency.
• The Fix: Insulating the firebox can help retain heat and improve combustion.
• Materials: Use high-temperature firebricks or ceramic fiber blankets.
• Installation: Line the firebox walls with firebricks or ceramic fiber blankets. Secure the insulation with high-temperature mortar or metal fasteners.
• Caution: Be careful not to block the air intake or exhaust vents.
• My Recommendation: I prefer firebricks for their durability and heat retention properties. Ceramic fiber blankets are easier to cut and shape, but they are less resistant to physical damage.

6. The Automatic Draft Control:

• The Problem: Maintaining a consistent draft can be challenging, especially in fluctuating weather conditions.
• The Fix: An automatic draft control system automatically adjusts the stove’s air intake to maintain a consistent draft. This improves combustion efficiency and reduces smoke emissions.
• Types: There are several types of automatic draft control systems available, including thermostatic dampers and electronic draft controllers.
• Installation: Follow the manufacturer’s instructions for installation.
• Benefits: Consistent heat output, reduced smoke, and improved fuel efficiency.

7. The Wood Gasification System (Advanced):

• The Problem: Traditional wood stoves burn wood directly, which can be inefficient and polluting.
• The Fix: A wood gasification system converts wood into gas, which is then burned in a separate combustion chamber. This results in a cleaner and more efficient burn.
• Complexity: This is a complex modification that requires significant engineering and fabrication skills.
• Benefits: Extremely clean burning, high heat output, and exceptional fuel efficiency.
• My Research: I’ve been researching wood gasification systems for years, and I’m convinced that they represent the future of wood heating. However, they are still relatively expensive and complex to implement.

Fine-Tuning Your Burning Technique

Even with all the upgrades in the world, your burning technique matters.

• Start with a Hot Fire: Get the fire burning hot quickly to establish a good draft and promote complete combustion. Use plenty of kindling and small pieces of wood.
• Maintain a Consistent Temperature: Avoid letting the fire smolder. Add wood regularly to maintain a consistent temperature.
• Air Control: Experiment with the air controls to find the optimal setting for your stove and wood type. Start with the air control fully open and gradually reduce it as the fire gets established.
• Observe the Smoke: Pay attention to the color and density of the smoke coming from the chimney. Clear or light gray smoke is a sign of efficient combustion. Dark or black smoke indicates incomplete combustion.

Safety First: Protecting Yourself and Your Home

Wood stoves are powerful tools, but they can also be dangerous if not used properly.

• Carbon Monoxide Detectors: Install carbon monoxide detectors on every level of your home, especially near sleeping areas.
• Smoke Detectors: Ensure your smoke detectors are working properly.
• Clearance to Combustibles: Maintain adequate clearance between the stove and combustible materials, such as furniture, curtains, and walls. Consult the stove’s manual for recommended clearances.
• Floor Protection: Place a non-combustible floor protector beneath the stove to protect the floor from sparks and embers.
• Chimney Inspections: Schedule regular chimney inspections to identify and address any potential problems.
• Fire Extinguisher: Keep a fire extinguisher nearby in case of emergency.

The Importance of Wood Species

The type of wood you burn significantly impacts the stove’s performance.

• Hardwoods vs. Softwoods: Hardwoods, such as oak, maple, and ash, are denser and burn longer than softwoods, such as pine and fir. Hardwoods also produce more heat per unit volume.
• Resin Content: Softwoods contain more resin than hardwoods. Burning resinous wood can lead to increased creosote buildup in the chimney.
• My Preference: I prefer burning a mix of hardwoods and softwoods. I use softwoods for starting the fire and hardwoods for maintaining a long-lasting burn.

The Economics of Wood Heating

Wood heating can be a cost-effective alternative to fossil fuels, but it’s important to consider all the costs involved.

• Wood Costs: The cost of firewood varies depending on the region and the type of wood. You can save money by cutting and splitting your own wood, but this requires time and effort.
• Equipment Costs: You’ll need to invest in a chainsaw, log splitter, and other tools.
• Maintenance Costs: Wood stoves require regular maintenance, including chimney cleaning and gasket replacement.
• My Calculation: I estimate that I save about $500 per year by heating with wood, compared to using propane. However, this doesn’t include the cost of my time and effort.

Understanding Creosote: The Silent Threat

Creosote is a flammable byproduct of incomplete combustion that accumulates in the chimney. It’s a major fire hazard.

• Formation: Creosote forms when smoke and gases cool as they travel up the chimney. The cooler the smoke, the more creosote will form.
• Types: There are three stages of creosote:
  • Stage 1: Light and flaky, easily removed with a chimney brush.
  • Stage 2: Hard and crusty, more difficult to remove.
  • Stage 3: Glazed and tar-like, extremely difficult to remove.
• Prevention: The best way to prevent creosote buildup is to burn dry wood and maintain a hot fire.
• Removal: Regular chimney cleaning is essential for removing creosote.

Advanced Splitting Techniques: Beyond the Maul

Splitting wood can be a physically demanding task, but there are techniques to make it easier.

• Hydraulic Log Splitters: These are the most efficient way to split large quantities of wood. They use hydraulic pressure to force a wedge through the log. I use a 27-ton log splitter, which can handle logs up to 24 inches in diameter.
• Manual Wedges: These are a good option for splitting smaller logs. Use a sledgehammer to drive the wedge into the log.
• Splitting Axe: A splitting axe is designed for splitting wood, with a wider head than a felling axe.
• My Tip: Always split wood along the grain. Look for cracks or knots in the wood, and split along those lines.

Drying Wood: The Science of Seasoning

Drying wood properly is essential for efficient combustion.

• Moisture Content: As mentioned earlier, the ideal moisture content for firewood is below 20%.
• Air Drying: This is the most common method of drying wood. Stack the wood off the ground in a sunny and windy location.
• Kiln Drying: This is a faster method of drying wood, but it’s more expensive. Kiln-dried wood typically has a moisture content of 10-15%.
• Drying Time: The drying time depends on the type of wood, the climate, and the stacking method. Hardwoods typically take longer to dry than softwoods.
• My Observation: I’ve found that wood dries faster when stacked in a single row, rather than a large pile.

The Future of Wood Heating: Innovations on the Horizon

Wood heating technology is constantly evolving.

• Gasification Stoves: These stoves convert wood into gas, which is then burned in a separate combustion chamber. This results in a cleaner and more efficient burn.
• Pellet Stoves: These stoves burn wood pellets, which are made from compressed sawdust and other wood waste. Pellet stoves are highly efficient and easy to operate.
• Smart Stoves: These stoves use sensors and electronics to optimize combustion and control the temperature.
• My Prediction: I believe that gasification stoves and smart stoves will become increasingly popular in the coming years, as people seek cleaner and more efficient ways to heat their homes with wood.

Grandma Bear: A Legacy of Warmth

The Fisher Stove Grandma Bear is a classic for a reason. It’s a simple, reliable, and powerful heating appliance. With a little care and attention, you can keep your Grandma Bear burning clean and efficiently for many years to come. Remember, a smoky stove is usually a sign of a problem that can be fixed. By following the steps outlined in this guide, you can diagnose the problem, implement the appropriate fixes, and enjoy the warmth and comfort of a well-tuned wood stove.

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